The surprising reason women are using Milk of Magnesia as makeup

The internet has exploded with beauty gurus proclaiming the benefits of Milk of Magnesia as an oil-controlling makeup primer, but does it really work? And is it a good idea to apply the product — billed as an oral laxative and antacid — directly on your face?

According to Lasaundra Lasker, an aesthetician and skin therapist at Ulta Beauty, the answer is yes — although dermatologists are more skeptical.

“I’ve been using Phillips’s Milk of Magnesia as my primer for years,” Lasker says. “It keeps oil at bay and helps set your makeup so it lasts longer.”

Lasker admits to being skeptical at first and a little concerned, too. “But it really works," she says. "It even reduces the appearance of enlarged pores.”

TODAY's YouTube Social Star, Angela Cruz, tested the claim for herself and wore Milk of Magnesia as an oil-preventing primer for an entire day. Her conclusion: It did offer a smoother, more finished look, but other products have done a better job at stopping shine for a full eight hours.

Although many of the reviews for this beauty trick have been positive, Dr. Rebecca Fitzgerald, a dermatologist based in Los Angeles, warns that the product could cause acne with repeated use. It could even trigger an allergic reaction for those with sensitive skin.

“Your skin's pH balance is a little acidic or neutral and Milk of Magnesia is at a basic pH. That could mess with your skin’s ability to hold water and it could cause you all kinds of problems,” Fitzgerald says.

Dr. Joshua Zeichner, a New York City-based dermatologist, says it's OK to use the product as an inexpensive alternative, but only on occasion.

“True makeup primers are engineered to do their job,” he says. “While Milk of Magnesia can serve a similar purpose when applied topically on your face, I would recommend using it only when you are in a jam, rather than for regular use.”

Beauty News with Angela Cruz / YouTube

Angela Cruz.

So, why does it work in the first place? The product’s active ingredient, magnesium hydroxide, helps dissolve fats and oils, Zeichner says.

Professional makeup artist and YouTube star Kandee Johnson says there's no need to resort to alternatives when there are great products on the market.